Need help in creating war for Guvnor from eclipse for customization

I have working knowledge of Guvnor. I want to customize few thing in guvnor. Please help me from where I can get source for Guvnor and work as a eclipse project. Also want to create war for same so that I can deploy in tomcat.

Thanks In Advance.

Ankush

subject: Need help in creating war for Guvnor from eclipse for customization